SLAC Modulator System Improvements and Reliability Results

A. Abstract In 1995, an improvement project was completed on the 244 klystron modulators in the linear accelerator. The modulator system has been previously described [ 11. This article offers project details and their resulting effect on modulator and component reliability. Prior to the project, we had collected four operating cycles (1991 through 1995) of MTTF data [2]. In this discussion, the '91 data will be excluded since the modulators operated at 60 Hz. The five periods following the '91 run were reviewed due to the common repetition rate at 120 Hz. B. Introduction The project objective aimed at improving modulator reliability and increasing mean time to faihue (MTTF) for specific components through the replacement of the old tbyratron trigger chassis and the installation of a hybrid anode reactor 131. MTTF data from '92 arxl '93, considered as " base " data, will be compared with data from '96 and '97/8, or accelerator runs after the improvement completion. These periods am based on the SLCXSLD experimental program because operation was especially critical and mquimd a high degtee of stability from every station: The 199415 accelerator mn was the period when the thyratron trigger improvement project was partially accomplished. Hence, a transitional offset appears in the '94/5 MTTF data.